Much of our understanding of the hemo-/hydrodynamics relating to CSF flow has come from Phase Contrast Magnetic Resonance Imaging (PC-MRI) experiments. PC-MRI uses the change in the phase of the MR signal, which occurs when fluid (such as blood or CSF) flows in a static magnetic gradient. This phase change is proportional to the fluid’s velocity. PC-MRI is a technique that provides qualitative and quantitative assessment of a moving fluid; thus, study of the CSF flow became one of its major applications. The keystone of PC-MRI is a bipolar gradient i.e., a gradient with the same positive and negative magnitude and the same application time of both. This bipolar gradient is placed in a sequence after the radiofrequency pulse and before data collection during echo time (TE). If the bipolar lobe is applied only in one axis, the gradient sensitises the image to the flow in just one direction. Knowing that, the application of a bipolar gradient in all three axes is necessary to develop a sequence sensitive to flow regardless of the direction. Phase-contrast MRI can be used for quantitative assessment of CSF flow, in which measurements such as flow velocity and volume are used to diagnose conditions and direct care in the appropriate patients. In addition, phase-contrast MRI enables qualitative assessment of CSF circulation (ie, bulk flow) and back-and forth motion (ie, pulsatile flow). One of the most widely used applications of CSF flow imaging is functional assessment of normal pressure hydrocephalus (NPH). Hyperdynamic flow of CSF is seen when there is enlargement of the ventricular system in the absence of or out of proportion to the sulcal enlargement (ventriculosulcal disproportion). Patients with NPH who have hyperdynamic CSF flow respond better to ventriculoperitoneal shunt placement than do patients with normal or decreased flow.